Ingredients:

4 jalapeno peppers, (*see note)
5 cloves garlic
1 1/2 teaspoons crushed dried oregano
1/2 teaspoon ground cumin
1 cup beef broth
1 tablespoon vegetable oil
1 1/2 cups beef broth
1/4 teaspoon salt
1/8 teaspoon ground black pepper
2 pounds beef sirloin roast
1 1/2 teaspoons vegetable oil

Method:

1. Preheat oven to 350°F (175°C).
In a heavy skillet, roast green chili peppers until browned, but not burned. Place in cold water and allow to soak for 30 minutes.
2. Roast garlic cloves in oven for about 15 minutes or until soft. Remove from oven ; cool, peel, and chop. Combine chilies, garlic, oregano, cumin, and beef broth. Process until smooth then strain through a medium sieve.
3. In a saucepan, heat 1 tablespoon oil. When hot, add the chili puree, reduce heat and simmer, stirring, until thickened, about 15 minutes. Add beef broth and cook for 45 minutes, stirring frequently. Season with salt and pepper. Brush over beef sirloin roast and marinate for 2 hours in refrigerator.
4. Preheat grill .
5. Grill for 20 to 25 minutes, or until meat reaches a temperature 140°F (60°C) for medium done. Brush often with 1 1/2 teaspoons oil. Reheat the sauce and serve over the sliced meat.